Re: [PATCH 3/5] irqchip/bcm2836: Make IPIs use handle_percpu_devid_irq()

From: Marc Zyngier <maz@kernel.org>
To: Guenter Roeck <linux@roeck-us.net>
Cc: Andrew Lunn <andrew@lunn.ch>,
	Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>,
	Jason Cooper <jason@lakedaemon.net>,
	Scott Branden <sbranden@broadcom.com>,
	Ray Jui <rjui@broadcom.com>,
	Gregory Clement <gregory.clement@bootlin.com>,
	linux-kernel@vger.kernel.org,
	Florian Fainelli <f.fainelli@gmail.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Valentin Schneider <valentin.schneider@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Subject: Re: [PATCH 3/5] irqchip/bcm2836: Make IPIs use handle_percpu_devid_irq()
Date: Tue, 15 Dec 2020 15:46:55 +0000	[thread overview]
Message-ID: <dff83a32c64bad6e3880dba8804cea6c@kernel.org> (raw)
In-Reply-To: <c9fb4ab3-a5cb-648c-6de3-c6a871e60870@roeck-us.net>

On 2020-12-15 15:39, Guenter Roeck wrote:
> On 12/15/20 7:26 AM, Marc Zyngier wrote:
>> On 2020-12-15 15:21, Guenter Roeck wrote:
>>> Hi Marc,
>>> 
>>> On 12/15/20 2:19 AM, Marc Zyngier wrote:
>>>> Hi Gunter,
>>>> 
>>>> On 2020-12-15 00:21, Guenter Roeck wrote:
>>>>> On Mon, Nov 09, 2020 at 09:41:19AM +0000, Valentin Schneider wrote:
>>>>>> As done for the Arm GIC irqchips, move IPIs to 
>>>>>> handle_percpu_devid_irq() as
>>>>>> handle_percpu_devid_fasteoi_ipi() isn't actually required.
>>>>>> 
>>>>>> Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
>>>>> 
>>>>> This patch results in boot failures (silent stall) for the qemu
>>>>> raspi2 emulation. Unfortunately it can not be reverted because
>>>>> handle_percpu_devid_fasteoi_ipi no longer exists in next-20201214,
>>>>> so I don't know if it is the only problem.
>>>> 
>>>> This is odd. This works just fine for me on both the RPi2 and 3
>>>> emulation, running a full Debian userspace. Could this be caused
>>>> by the version of QEMU you are using? Here's what I have:
>>>> 
>>>> $ qemu-system-arm --version
>>>> QEMU emulator version 5.1.0 (Debian 1:5.1+dfsg-4+b1)
>>>> 
>>> 
>>> I used qemu 5.0 which - up to now - worked fine. Let me try with
>>> 5.1 and 5.2. Sorry, I should have tried first before bothering you.
>> 
>> No bother at all. If this works for you on more recent versions of
>> QEMU, that'd be an interesting data point. I'm also interested in
>> the result of the patch either way.
>> 
> 
> It doesn't work for me with qemu 5.1, nor with qemu 5.2. My userspace
> is generated with buildroot, busybox-based, and very basic.

OK, so something is definitely different between our setups.
Mind pointing me to your config and your QEMU invocation?

> 
> Your patch fixes the problem for me, though, so feel free to add
> 
> Tested-by: Guenter Roeck <linux@roeck-us.net>
> 
> if/when you submit it.

Thanks for that.

         M.
-- 
Jazz is not dead. It just smells funny...

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